LQB185 Chapter Notes - Chapter 20: Dense Irregular Connective Tissue, Pericardium, Mediastinum
25 May 2018
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Chapter 20 The Cardiovascular System: The Heart
20.1 Anatomy of the Heart
➢ Heart is 12cm (long) 9cm (wide) 6cm (thick)
➢ Heart lies in the mediastinum
➢ Pericardium
- The membrane that surrounds and protects the heart
- It confines the heart too its position, while allowing small freedom of
movement for contraction.
- 2 parts:
1. Fibrous pericardium (superficial)
-tough, inelastic, dense irregular connective tissue- prevents
overstretching of the heart, provides protection and anchors heart
to mediastinum.
2. Serous pericardium (deep)
-thinner, delicate membrane that forms a double layer around the
heart. Outer layer is called Parietal layer of serous pericardium
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(fused to the fibrous layer) and inner layer called Visceral layer of
the serous pericardium (adheres tightly to surface of heart).
- Pericardial Fluid: a thin film of lubricating serous fluid between
these two layers of serous pericardium
- Pericardial Cavity: space that contains the pericardial fluid.
➢ Layers of the Heart Wall
- Epicardium (External Layer)
- Myocardium (Middle Layer)
- Endocardium (Inner Layer)
➢ Epicardium
- Composed of 2 tissue layers:
- Outermost (visceral layer)-
thin transparent layer
composed of mesothelium.
- Innermost- layer of delicate
fibroblastic tissue and adipose tissue
➢ Myocardium
- Responsible for pumping action of the
heart and composed of cardiac
muscle tissue.
- 95% of heart wall
➢ Endocardium
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Document Summary
Heart is 12cm (long) 9cm (wide) 6cm (thick) The membrane that surrounds and protects the heart. It confines the heart too its position, while allowing small freedom of movement for contraction. Tough, inelastic, dense irregular connective tissue- prevents overstretching of the heart, provides protection and anchors heart to mediastinum: serous pericardium (deep) Thinner, delicate membrane that forms a double layer around the heart. Outer layer is called parietal layer of serous pericardium (fused to the fibrous layer) and inner layer called visceral layer of the serous pericardium (adheres tightly to surface of heart). Pericardial fluid: a thin film of lubricating serous fluid between these two layers of serous pericardium. Pericardial cavity: space that contains the pericardial fluid. Outermost (visceral layer)- thin transparent layer composed of mesothelium. Innermost- layer of delicate fibroblastic tissue and adipose tissue. Responsible for pumping action of the heart and composed of cardiac muscle tissue. Thin layer of endothelium overlying a thin layer of connective tissue.
